"Name and address withheld."

To protect the (unwittingly?) guilty.

I suspect a few of you may have seen this place

I'm not 100% sure, but I suspect, had I still been a smoker, my reaction would have been the same...

"HELL, that can't be legal."

I was pretty sure I knew the regs, but checked anyway.
The 1st/clearest I found was at Wrexham County Borough Council: where I read...
"If the room has an opening i.e. empty space or gaps such as missing walls (but not doors or windows) which are open to the outside air of less than half the area of its perimeter it is substantially enclosed."

This "great erection" was, in fact, only surrounded on two sides, but I doubt if the fact that the third side was a mere 6-12" away from the outer wall and the fact that you had to enter the "Smoking Shelter" to access the cafe helped its legality in any way.